This invention relates to novel antigenic compositions useful in diagnostic testing for the presence of Campylobacter jejuni ("C. jejuni") or Campylobacter coli ("C. coli") infection, and useful as vaccines for providing immunological protection against such infection. In certain embodiments, antibodies raised against the novel antigenic compositions may also be used for diagnostic testing for C. coli or C. jejuni.
C. jejuni and C. coli are believed to cause both inflammatory and non-inflammatory gastroenteritis (Blaser et al., "Campylobacter enteritis," N. Eng. J. Med., 1981; 305:1444-1452). They are recognized as leading causes of inflammatory diarrhea in the U.S. and other developed countries (Blaser et al., Campylobacter enteritis in the United States: A Multicenter Study," Ann. Intern. Med., 1983;98:360-365), and are also important causes of endemic diarrheal disease in the developing world (Glass et al., "Epidemiological and Clinical Features of Endemic Campylobacter jejuni infection in Bangladesh," J. Infect. Dis., 1983;148:292-296). They have further been recognized as common causes of traveller's diarrhea. Additionally, in the U.S. and other developed countries it has been recognized that C. jejuni and C. coli are commonly found in many different types of food animals, including cattle, sheep, goats, swine, chickens, ducks and turkeys. Raw milk may be contaminated with C. jejuni. Although contaminating organisms are readily killed by pasteurization, many persons consume unpasteurized milk, especially in rural areas. Surface water may be contaminated with C. jejuni or C. coli, and persons who consume such water may become ill. Commercially raised poultry are particularly susceptible to contamination with these pathogens (Blaser et al., Epidemiology of Campylobacter jejuni Infections, Epidemiologic Reviews, 1983;5:157-176). Many of the animals used as pets by humans, including dogs, cats, and birds may be infected with these organisms, may become ill as a result of infection, or may transmit the organisms to humans. For all of these reasons, it is important that accurate and rapid diagnostic tests be developed for detection of the infections.
Because C. jejuni and C. coli, are fastidious to culture, sophisticated and time-consuming techniques are required to isolate and identify these organisms in a microbiology laboratory. Even with optimal technique, the present culture systems may still yield falsely negative culture results. Improved methods for the rapid and accurate detection of C. jejuni and C. coli infection are needed.
It is known that persons infected with C. jejuni or C. coli develop antibodies specific to the organisms (Blaser et al., "Human Serum Antibody Response to Campylobacter jejuni as Measured in an Enzyme-Linked Immunosorbent Assay", Infect Immun., 1984;44:292-298). Numerous studies have determined that prior C. jejuni or C. coli infection can be recognized in serological assays. Immunological testing can be inaccurate, however, unless the antigens used include a high concentration of conserved antigens with both a high affinity and a high specificity for the antibodies being detected. The presence of antigens which are not sufficiently unique to attract only C. jejuni or C. coli-specific antibodies can lead to the formation of non-specific antigen/antibody complexes and therefore to false positive test results. Conversely, antigens which are not common to most C. jejuni and C. coli strains, or which do not produce strong immunogenic responses to most C. jejuni or C. coli-specific antibodies may not bind the C. jejuni or C. coli-specific antibodies of patients infected with certain strains, thus leading to false negative test results. In such cases, the failure of antigen/antibody complexes to form does not necessarily indicate lack of infection but rather an insensitivity of the test system. Adequate sensitivity often coincides with inadequate specificity, and vice-versa.
Studies performed with human volunteers have shown that the prior exposure to experimental C. jejuni infection offers some protection against subsequent C. jejuni disease. (Black et al., "Experimental Campylobacter jejuni Infection in Humans," J. Infect. Dis., 1988;157:472-479; Perlman et al., "Humoral Immune Response to Campylobacter jejuni in Human Volunteers," Abstract presented at the 87th Annual Meeting of the American Society for Microbiology, Atlanta, Ga., March 1987; Perlman et al., "Immunity to Campylobacter jejuni Following Oral Challenge to Volunteers," Abstract presented at the Fourth International Workshop on Campylobacter Infections, Goreborg, Sweden, June 1987.) Similarly, individuals with prior exposure to unpasteurized milk and high pre-existing levels of anti-C. jejuni antibodies have appeared to be at decreased risk of illness when exposed to milk contaminated with C. jejuni (Blaser et al., "The Influence of Immunity on Raw-Milk Associated Campylobacter Infections,"JAMA 1987;257:43-46.) However, while this work indicates that exposure to whole bacteria may induce a protective host response, the pathogenicity of live C. jejuni and C. coli limits the utility of a whole cell vaccine. Conversely a vaccine composed solely of purified C. jejuni antigens in an appropriate vehicle, or a genetically engineered recombinant vaccine where the C. jejuni antigen was presented by an avirulent bacteria or virus, would require use of an antigen capable of inducing the desired immune response in most recipients.
Certain surface proteins of C. fetus are disclosed by "Purification and Characterization of a Family of High Molecular Weight Cell Surface Proteins from Campylobacter fetus," Biol Chem., 1988;263:6416-6420.
In Miotti, "Rapid Methods for the Molecular Diagnosis of Infectious Diseases: Current Trends and Applications," Eur. J Epidemiol., 1987; 3:356-364, immunological methods are disclosed for detection of infectious agents, but Miotti does not teach a satisfactory diagnostic test for C. jejuni or C. coli.
In co-pending U.S. patent application Ser. No. 07/158,003, filed Feb. 18, 1988, Blaser et al. disclose antigenic compositions for use in detecting antibodies specific for Campylobacter [Helicobacter] pylori.
Outer membrane proteins of C. jejuni having molecular weights of 29 kDa, 30 kDa and 31 kDa are discussed In Blaser et al., "Campylobacter jejuni outer membrane proteins are antigenic for humans," Infection and Immunity, vol. 43, No. 3, pp. 986-93 (March 1984). Several minor proteins (29-31 kDa) were found to be immunogenic by immunoblotting in Dunn et al., "Two-Dimensional Gel Electrophoresis and Immunoblotting of Campylobacter Outer Membrane Proteins," Infection and Immunity, vol. 55, No. 7 pp. 1564-72 (July 1987),
U.S. Pat. No. 4,404,194 discloses that a 90 kDa protein from C. jejuni has immuno-suppressive activity.
U.S. Pat. No. 4,785,086 discloses a DNA probe for detecting C. jejuni.
U.S. Pat. No. 4,882,271 discloses a 300-700 kDa antigen from Campylobacter pylori and its use in various assays.